Infections caused by beta-lactamase-producing Fusobacterium spp. in children.
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Biomedical subjects
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Aspirates from pyogenic liver abscesses obtained from 14 children were cultured for aerobic and anaerobic bacteria. Of 29 organisms that were recovered, 17 were anaerobic and 12 were aerobic or facultative. The predominant organisms were Peptostreptococcus spp. (5 isolates). Bacteroides fragilis group (4), Fusobacterium spp. (3) and Staphylococcus aureus (4). Aerobic or facultative bacteria only were recovered in five cases, anaerobic bacteria only in four and mixed aerobic and anaerobic bacteria in five. Anaerobic bacteria were recovered in liver abscesses that were associated with other infection in which these organisms were predominant (i.e. abdominal infection, abscesses). This study highlights the potential importance of anaerobic bacteria in pyogenic liver abscess.
Therapy with ofloxacin, ciprofloxacin, and lomefloxacin (alone or in combination with clindamycin) and therapy with sparfloxacin, clinafloxacin, and temafloxacin alone were given to mice with subcutaneous abscesses. The abscesses were caused by two Bacteroides fragilis isolates, one of which was susceptible and one of which was resistant to ofloxacin, ciprofloxacin, and lomefloxacin, alone or in combination with Escherichia coli. The abscesses were examined 5 days after inoculation. Numbers of B. fragilis organisms reached log10 10.2 to 11.8 per abscess, and numbers of E. coli organisms reached log10 10.6 to 11.8 per abscess. All of the quinolones reduced the number of susceptible B. fragilis isolates (log10 3.6 to 6.9) and E. coli isolates (log10 5.7 to 6.8). However, ciprofloxacin and lomefloxacin failed to reduce the number of resistant B. fragilis organisms in single-organism or mixed infections. The addition of clindamycin to either ofloxacin, ciprofloxacin, or lomefloxacin reduced the numbers of both susceptible and resistant B. fragilis organisms (log10 3.8 to 7.8). In contrast, sparfloxacin, clinafloxacin, and temafloxacin were effective as single therapy in eradicating B. fragilis resistant to ofloxacin, ciprofloxacin, and lomefloxacin. These in vivo data confirm the in vitro activity of these quinolones and suggest that although ofloxacin, ciprofloxacin, and lomefloxacin are occasionally effective as single agents in eradicating mixed infection by susceptible strains of B. fragilis and E. coli, addition of an agent with activity against anaerobic organisms will ensure their efficacy. Quinolones with good efficacy against B. fragilis may be effective as single-agent therapy of mixed infections.
The in vivo effects of penicillin and cefprozil therapy on the interaction between organisms commonly recovered from inflamed tonsils were studied by using a subcutaneous abscess model in mice. These organisms were group A beta-hemolytic streptococci (GABHS), Streptococcus salivarius (which is capable of interfering with GABHS), and Staphylococcus aureus. In mice infected with GABHS and S. salivarius alone or in combination, penicillin eliminated both organisms and cefprozil eliminated GABHS and S. aureus but not S. salivarius. Penicillin did not, however, reduce the number of GABHS or S. salivarius in the presence of S. aureus. The present study demonstrated the ability of beta-lactamase-producing S. aureus to protect GABHS from penicillin. However, no such protection was present following the administration of cefprozil. Furthermore, the preservation of S. salivarius that interferes with GABHS growth may provide protection from reinfection with GABHS. This study supports and provides an explanation for the increased efficacies of cephalosporins administered orally over that of penicillin when treating patients with acute GABHS pharyngitis or tonsillitis.
Cefoxitin, cefotetan, and cefmetazole were compared in 10-day therapy of intra-abdominal and subcutaneous infections caused by three organisms: Bacteroides fragilis and Bacteroides thetaiotaomicron combined with either Escherichia coli or Staphylococcus aureus. Intra-abdominal infection was caused by B. fragilis plus B. thetaiotaomicron plus E. coli. Therapy was initiated immediately before inoculation or was delayed for 8 h. Mortality was 14 of 30 (47%) for saline-treated mice, and all survivors developed abscesses. Immediate therapy reduced mortality and the percentage of mice with abscesses (in survivors), respectively, to 17 and 20% with cefoxitin, 0 and 13% with cefotetan, and 0 and 17% with cefmetazole, and the numbers of all bacteria were reduced by all the cephalosporins. Delayed therapy reduced mortality and abscess formation, respectively, to 20 and 8% of mice with cefoxitin, 10 and 93% with cefotetan, and 7 and 96% with cefmetazole. B. thetaiotaomicron survived in all abscesses treated with cefotetan and cefmetazole. Subcutaneous abscesses were caused by each organism alone or in combinations of one aerobe (S. aureus or E. coli) and one or two Bacteroides species. Early therapy reduced the numbers of all bacteria independent of their in vitro susceptibility. All agents reduced the number of each Bacteroides species with either E. coli or S. aureus. However, when therapy was delayed, cefotetan and cefmetazole were less effective than cefoxitin against B. thetaiotaomicron. Cefotetan was the most active agent against E. coli, and cefmetazole was the most effective against S. aureus. These data illustrate the efficacy of all tested cephalosporins in the prophylaxis of polymicrobial infections.
Opportunistic bacterial infections are the predominant cause of death following myelosuppressive radiation exposure. When used alone, a variety of immunomodulators and antibiotics have been reported to reduce radiation-induced death. In these studies, the combined therapeutic effects of the immunomodulator glucan and the quinolone antibiotic pefloxacin were evaluated for survival-enhancing effects in myelosuppressed C3H/HeN mice. Mice were exposed to 7.9 Gy of whole-body 60Co radiation and treated with saline, glucan (250 mg/kg of body weight intravenously, 1 h after irradiation), pefloxacin (64 mg/kg/day orally, days 3 to 24 after irradiation), or glucan plus pefloxacin. Survival 30 days after irradiation in mice receiving these respective treatments was 25, 48, 7, and 85%. Evaluation of granulocyte-macrophage progenitor cell (GM-CFC) recovery in mice receiving these treatments revealed that, compared with recovery in saline-treated mice, glucan stimulated GM-CFC recovery, pefloxacin suppressed GM-CFC recovery, and glucan administered in combination with pefloxacin could override pefloxacin's hemopoietic suppressive effect.
The role of three oral flora organisms (Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) was investigated in 31 children with recurrent nonstreptococcal tonsillitis. Antibody titers to the three organisms were measured by enzyme-linked immunosorbent assay in the 31 patients, as well as in 32 control patients who had not suffered from recurrent tonsillitis. None of the individuals in either group suffered from periodontal or dental illness. Significantly higher antibody levels to P intermedia were found in the study group as compared to controls (median 91.0 versus 72.5; p = .02). In contrast, the antibody titers to the other two organisms were generally low (less than 0.30), and no difference was found among the two study groups. The elevated antibody levels to P intermedia, a known oral pathogen that is also isolated from most recurrently inflamed tonsils, suggest a pathogenic role for this organism in recurrent tonsillitis.
The microbiology and clinical features of empyema were studied retrospectively in 197 patients whose specimens yielded bacterial growth after inoculation for aerobic and anaerobic bacteria. Three hundred forty-three organisms (216 aerobic or facultative and 127 anaerobic organisms) were isolated. Aerobic bacteria were isolated in 127 (64 percent) patients, anaerobic bacteria in 25 (13 percent), and mixed aerobic and anaerobic bacteria in 45 (23 percent). The predominant aerobic or facultative organisms were Streptococcus pneumoniae (70 isolates), Staphylococcus aureus (58), Escherichia coli (17), Klebsiella pneumoniae (16), and Haemophilus influenzae (12). The predominant anaerobes were pigmented Prevotella and Porphyromonas species (24), Bacteroides fragilis group (22), anaerobic cocci (36), and Fusobacterium species (20). beta-Lactamase-producing organisms were recovered in 49 (38 percent) of 128 tested specimens. These included all 42 tested S aureus and 15 B fragilis group, 4 of 9 K pneumoniae, 3 of 9 H influenzae, 3 of 8 pigmented Prevotella and Porphyromonas species, and 2 of 6 E coli. Most patients from whom S pneumoniae and H influenzae were recovered had pneumonia, and most patients with S aureus had pneumonia, aspiration pneumonia, and lung abscesses. The recovery of anaerobic bacteria was mostly associated with the concomitant diagnosis of aspiration pneumonia, and lung, subdiaphragmatic, dental, and oropharyngeal abscesses. These data highlight the importance of anaerobic bacteria in selected cases of empyema.
Intra-abdominal infections in children that follow perforation of viscus often involve the gastrointestinal aerobic and anaerobic bacterial flora. These organisms possess various virulence factors and exhibit potential synergy. The intra-abdominal infection is biphasic, with the Enterobacteriaceae as the major pathogens in the peritonitis stage, and the Bacteroides fragilis group predominating in the abscess stage. Experiments with animals and experience in patients support the need to use single or combined antimicrobial agent therapy that is effective against both Enterobacteriaceae and the B. fragilis group.
Skin and soft tissue infection and cutaneous abscesses are common in children. They may be polymicrobial in nature, especially when located proximal to mucous membranes. A general knowledge of the common causative bacterial organisms in these infections enables the physician to empirically institute antimicrobial therapy before culture results are available. This review assesses the number and types of aerobic and anaerobic bacteria that occur in skin and soft tissue infections in children. Staphylococcus aureus and Streptococcus pyogenes were recovered from infections occurring at all body sites, but predominated in infections of the leg, neck, and hand. Group D streptococci, Enterobacteriaceae, Neisseria gonorrhoeae, Bacteroides fragilis, and Prevotella species were isolated mostly from infections of the external genitalia and perirectal areas; pigmented Prevotella and Porphyromonas and Haemophilus influenzae can be isolated from infections of the head and neck. Management of skin and soft tissue infections in children should include surgical and medical therapy.
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The microbial content of fourteen bars of soap in a household setting was studied. The number of bacteria isolated from heavily used soaps which were wet, all placed in one bathroom, were higher than from infrequently used soaps that were dry and were placed in another bathroom. The major bacteria isolated were Staphylococcus sp. and Enterobacteriaceae.
The bacteriological quality of the canal system in Amsterdam was assessed by determination of the quantity and quality of the water. Eight samples of water from different canals were studied. No Gram-positive bacteria were found. The number of Gram-negative bacteria varied from 720-1,820 (average 1,250) organisms per ml of water. The predominant bacteria were: Pseudomonas sp., Klebsiella pneumoniae and Escherichia coli. These data illustrate the high number of potential pathogens in the water canal system in Amsterdam.
Of all the salivary glands, the parotid gland is most commonly affected by an inflammatory process. Infections of the parotid gland range from acute to severe. Assessment of the disease process should differentiate local primary parotid infection from systemic infection when this gland is also involved as part of a generalized inflammatory condition. Viral parotitis can be caused by paramyxovirus (mumps), Epstein-Barr virus, coxsackievirus, and influenza A and parainfluenza viruses. Acute suppurative parotitis is generally caused by Staphylococcus aureus, Streptococcus species, and rarely, gram-negative bacteria. Anaerobic bacteria, mostly Peptostreptococcus species and Bacteroides species, and pigmented Porphyromonas species and Prevotella species have been recently recognized as an important cause of this infection. beta-Lactamase-producing organisms can be isolated in almost three fourths of the patients. Predisposing factors to suppurative infections are dehydration, malnutrition, oral neoplasms, immunosuppuration, sialolithiasis, and medications that diminish salivation. Pus, aspirated from a suppurative parotic abscess, should be plated on media that are supportive for the growth of aerobic and anaerobic bacteria, mycobacteria, and fungi. Early and proper antimicrobial therapy may prevent suppuration. Initial empiric therapy that is directed against both aerobic and anaerobic bacteria may be required until a specific causal diagnosis is available. Surgical drainage may be indicated when pus has formed. This may prevent complications and facilitate recovery.
The presence of encapsulated and piliated Bacteroides spp. (mostly Bacteroides fragilis and melaninogenicus groups was investigated in isolates from blood, abscesses and normal flora. Of the strains of Bacteroides spp. isolated 45 of 54 (83%) recovered from blood and 31 of 40 (78%) found in abscesses were encapsulated. In contrast, only seven of 71 (10%) similar strains isolated from the faeces or pharynx of healthy persons were encapsulated (P < 0.001). Pili were observed in three of 54 (6%) of strains isolated from blood, 30 of 40 (75%) of those recovered from abscesses (P < 0.001), and 49 of 71 (69%) of those found in normal flora (P < 0.001). The predominance of encapsulated forms in all strains of B. fragilis and B. melaninogenicus in blood as well as in abscesses suggests an increased virulence of these compared with non-encapsulated isolates. In contrast, the presence of pili in Bacteroides spp. recovered mostly from abscesses and normal flora suggests that this structure may play a role in the ability of these organisms to adhere to mucous membranes and may interfere with their ability to spread systemically. These findings illustrate the morphological differences that may be observed in Bacteroides spp. from various anatomical sites.
We demonstrated that glucan, a beta-1,3 polysaccharide immunomodulator, enhances survival of mice when administered before radiation exposure. Glucan's prophylactic survival-enhancing effects are mediated by several mechanisms including (1) increasing macrophage-mediated resistance to potentially lethal postirradiation opportunistic infections, (2) increasing the D(o) of hematopoietic progenitor cells, and (3) accelerating hematopoietic reconstitution. In addition, even when administered shortly after some otherwise lethal doses of radiation, glucan increases survival. Glucan's therapeutic survival-enhancing effects are also mediated through its ability to enhance macrophage function and to accelerate hematopoietic reconstitution; glucan's therapeutic potential, however, is ultimately dependent on the survival of a critical number of hematopoietic stem cells capable of responding to glucan's stimulatory effects. Preirradiation administration of the traditional aminothiol radioprotectants WR-2721 and WR-3689 has been previously demonstrated to be an extremely effective means to increase hematopoietic stem cell survival. Therapeutic glucan treatment administered in combination with preirradiation WR-2721 or WR-3689 treatment synergistically increases both hematopoietic reconstitution and survival. Such combined modality treatments offer new promise in treating acute radiation injury.
Otitis media (OM) is a common childhood disease and one which can cause significant morbidity. A knowledge of the pathogens responsible for OM enables the most appropriate treatment regimen to be selected and thus minimizes further complications which may require hospital admission and surgery. The microbiology of acute, serous and chronic OM is reviewed, with particular regard to the role of anaerobic bacteria. Anaerobes, mainly Gram-positive cocci, have been recovered from 25% of the ear aspirates of patients with acute otitis media. In a study of serous OM, anaerobic bacteria were recovered in 12% of the culture-positive aspirates. The predominant anaerobes were Gram-positive cocci and pigmented Prevotella. Several studies have reported the recovery of anaerobes from about 50% of patients with chronic OM and those with cholesteatoma. The predominant anaerobes were Gram-positive cocci, pigmented Prevotella, Porphyromonas sp., Bacteroides spp. and Fusobacterium spp. Many of these organisms produce beta-lactamase which might have contributed to the failure of the patients to respond to penicillins. The appropriate antimicrobial therapy for acute, serous and chronic otitis media is discussed.
Microbiological and clinical data from 46 patients with external otitis were retrospectively evaluated. Specimens were processed for isolation of aerobic and anaerobic bacteria. A total of 42 aerobic bacteria, 22 anaerobic bacteria, and 3 Candida albicans organisms were recovered. Aerobic bacteria only were isolated from 31 patients (67%), anaerobic bacteria only were isolated from 8 (17%), and mixed aerobic and anaerobic bacteria were isolated from 4 (9%). C. albicans alone was recovered from two patients (4%), and the organism was mixed with aerobic bacteria in one case (2%). The most common isolates were Pseudomonas aeruginosa (19 instances), Peptostreptococcus species (11), Staphylococcus aureus (7), and Bacteroides species (5). One isolate was recovered from 30 patients (65%), 2 isolates were recovered from 11 (24%), and 3 isolates were recovered from 5 (11%). beta-Lactamase activity was detected in 32 isolates recovered from 27 specimens (59%). These data illustrate the polymicrobial nature of external otitis in one-third of the patients and the role of anaerobic bacteria in one-quarter of them. Further prospective studies are warranted for evaluating the role of anaerobic bacteria in this infection and the therapeutic implications of these findings.